This invention relates generally to apparatus for sampling a liquid medium and more particularly to remotely located apparatus for obtaining samples at discrete points in time, analyzing the samples, transmitting data while the apparatus remains submerged, and preserving the samples for laboratory analysis.
In water body research considerable difficulties have been experienced in the interpretation of remote measurements, particularly in measuring changes in water quality, mainly because of the problems of correlating surface measurements with actual conditions. A primary reason for this poor correlation is the lag time between obtaining a sample and its analysis. The chemical and biological characteristics of a sample may be altered drastically if the time interval between sample taking and sample analysis becomes excessive. Further, water conditions can vary, for example with the tide or time of day, these changes being unnoticed unless discrete samples are taken over a period of time at the same location.
Closely associated with the deterioration of a sample with time is the taking of a false sample. Prior sampling devices have had an external cavity surrounding a valved sample entranceway. Stagnant water collecting in this cavity may not be representative of the actual water conditions at the time a sample is taken, but nonetheless constitute a portion of the water sample taken.
Another problem associated with sample devices capable of providing on-site analysis is accurate control of the volume of water constituting each sample. Certain sensors require that sample volume be controlled in order to obtain useful information. It is further necessary that all volumes are consistent where a number of samples are taken at various times and comparisons are made between the samples.
Clearly there is a need in the art for a water monitoring apparatus which is capable of remote operation and which is able to take a number of samples of constant volume representative of the surrounding water body when taken. Furthermore, there is need for an apparatus capable of specimen analysis while submerged; capable of transmitting the data obtained to a surface location and which also preserves the samples for on-shore examination.
Therefore, it is an object of the present invention to provide a water monitoring device which takes representative water samples at desired intervals.
It is a further object of the present invention to provide a water monitoring device which takes a plurality of samples, each of a controlled volume, and stores them for above-surface examination.
It is another object of the present invention to provide a water monitoring device capable of sample analysis while remaining submerged.
It is an additional object of the present invention to provide a water monitoring device which takes samples upon command from a remote surface station.
It is a further additional object of the present invention to provide a water monitoring device which provides data from sample analysis to a remote surface station while remaining submerged.